I'm only expecting Age of Empires and/or Gears 5 Horde Reveal.
Congrats on Writer.
Gears Tactics is well suited for Gamescom.
In addition to what you guys mentioned, we could see the dates of Bleeding Edge beta and Wasteland 3 alpha. They could talk about Flight simulator since I think it will do well in Europe and especially Germany. I don't any of the studios is ready to show anything completely new.
By the way, it is a good venue to formally announce the new studio working on AoE.
Xbox being on PC and Steam will open a lot of doors in Europe. Now, they can do two proper conferences. Console focused on E3 and PC focused on Gamescom, with a nice refresh at the end of the year on X0 events.